Answer:
5 hours
Step-by-step explanation:
Time taken for trip : t + 1
Time taken for return : t
Avg. speed (trip) : 256 km/h
Avg. speed (return) : 320 km/h
The distances covered on both trips are equal.
⇒ Distance (trip) = Distance (return)
⇒ Speed (trip) × time (trip) = Speed (return) × time (return)
⇒ (256)(t + 1) = (320)(t)
⇒ 256t + 256 = 320t
⇒ 64t = 256
⇒ t = 4 hours
<u>Time (trip)</u> = t + 1 = 4 + 1 = 5 hours
the formula for the area of a triangle is 1/2 (base x height) so 1/2 of 20 is 10 ,you do 10 times 12 which is 120. So the area is 120 sq cm.
Answer
A, B, C, D, E, F.
In all of these shapes, the description applies to all except the trapezoid.
75 degrees and 105 degrees
Supplementary angles are those angles that sum up to 180 degrees
So angle A + B = 180 or B = 180 - A
then A/B = 5/7
7A = 5B
7A = 5(180 - A)
7A = 900 - 5A
12A = 900
A = 75
then B = 180 - A = 180 - 75 = 105
C = R - p
add C to both sides
R = C + p
subtract p from both sides
R - p = C ⇒ C = R - p
. Profit function is 
. And the revenue function is 
. In a day, bookstore must sell at least 15 books, because of 6n-90=0, in order to make profit.